pritchard



(No Model.) 3 Sheets-Sheet 1. N. J. PRITOHARD.

AIR BRAKE.

Patented Sept. 10, 1889.

Wtllmga o-ea mwnzns mmum mr. Wishingion, ma

(No Model.) 3 Sheets-Sheet 2. N. J. PRITGHARD.

AIR BRAKE.

No. 410,922. Patented Sept. 10, 1889.

(No Model.) 3 Sheets-Sheet 3. N. J. PRITGHARD.

AIR BRAKE.

Patented Sept. 10, 1889.

n. PETERS." man- Wahhgtnn, n. c.

UNITED STATES PATENT OF ICE.

NATHANIEL J. PRITCIIARD, OF ROANOKE, VIRGINIA, ASSIGNOR TO THE PRITOHARD BRAKE COMPANY, OF SAME PLACE.

.AlR-BZRAKE.

SPECIFICATION forming part of Letters Patent No. 410,922, dated SeptemberlO, 1889. Application filed October 20, 1888. Serial No. 288,618. (No model.)

To a whom'it may concern: ment beneath the car or other structure with Be it known that I, NATHANIEL J. PRITCH- which it is used. It maybe made in one or ARD, a citizen of the Unit-ed States, residing more parts, as preferred. I have represented at Roanoke, in the county of- Roanoke and in the drawings a convenient way of making State of Virginia, have invented certain new it, it being shown as consisting of the main and useful Improvements in Air-Brakes; and cylindrical body A, upon the top of which is I do hereby declare the following to'be a full, secured the convex head A, while the lower clear, and exact description of the invention, part is closed by the convex end piece A such as will enable others skilled in the art Within this casing are located two horizontal IO to which it appertains to make and use the diaphragms or partitions of gum,gutta-percha, same. rubber,or other elastic substance or material, My invention relates to an improvement in the edges of the upper of said diaphragms B devices for applying and relieving the pressbeing secured between the convex head A and ure on railway-brakes, the object thereof in the main cylindricalbodyA,while the edges of 15 part being to simplify and make more effithe lower of said diaphragms B are secured cient the device whereby the admission of between the end piece A and the main body. airto the brakecylinder is regulated and con- These elastic diaphragms, being of elastic trolled, and also to so regulate the exhaust material, will (under the pressure of the air) that the engineer may better adjust and hold be expanded or contracted, so as to take either 20 any desired degree of pressure upon the the position shown in Fig. 1 or that shown in brakes; and the invention consists, essen- Fig. 2 or, if the air-pressures above and below tially, in the construction, arrangement, and the same should exactly balance, the diacombination of parts, substantially as will be phragms might at certain times be accurately hereinafter described and claimed. horizontal. v 25 In the accompanying drawings, illustrating The casing is provided with ports at points my invention, Figure 1 is a vertical section where the several pipes are coupled thereto, of my improved device for applying pressure which are used with the ordinary air-brake to pneumaticrailway-brakes,togetherwith the and lead to the essential parts of the same. engineers valve, the train supply-pipe, and Thus a denotes the portnear the upper end 0 the train exhaust-pipe, the several parts beof the casing above the upper diaphragm B, So ing shown in the position that they assume where a coupling is made with the pipe that 7 when the brakes are released. Fig. 2 is averleads to the auxiliary reservoir or air-drum. b tical section similar to that of Fig. 1, the parts is the port in the wall of the main cylindrical being in the position that they occupy when body A between the two diaphragms, where 3 5 the brakes are set. Fig. 3 is ahorizontal parthe pipe is connected leading to the braketial section on the line a: .120 of Fig. 1. Fig. 4 cylinder. 0 is a port located near the lower is a horizontalpartial section on the line y y end of the case below the diaphragm B, r of Fig. 1. Fig. 5 is a'detail section of the enwhere a connection is made with the main gineers valve and certain of the adjacent trainpipe O, that supplies air from the air- 40 parts, showing the arrangement of the same reservoir to the device. d is the exhaust-port 0 when straight airis to be applied to the brakes. in the internal horizontal tubular extension Like letters of reference designate corre A of the main cylindrical portion A of the sponding parts throughout the several figcasing, and at the point where said port is ures. located the train exhaust-pipe is coupled to 5 The casing within which the essential parts the casing, which exhaust-pipe runs from said of my improved device for applying pneucasing to theengineers valve, and into it the matic press ure to railway-brakes are arranged air is exhausted. is preferably of a general cylindrical form hav- Centrally within the space between the two ing any suitable dimensions and made in any diaphragms is located a light metallic casting 5o desired manner, it being adapted for arrangeor frame having an eccentric vertical stem E, xoo

recessed to contain a valve, as will be hereinafter explained. This vertical stem is integral at its upper end with a flat plate E, that rests in contact with the under surface of the diaphragm B, and has a sleeve or bushing E projecting upward through a central opening in said diaphragm. A washer G encircles the sleeve E and rests close upon the top of the diaphragm B, and an open slotted or cagelike cap or head F is firmly screwed upon the sleeve E down upon the washer. In this way the central casting is securely fastened to the upper diaphragm. The lower end of the eccentric stem E is integral with the fiat portion E, which rests in close contact with the upper surface of the diaphragm B, and has a central projection E, that extends downward through the diaphragm, receiving upon its lower end a washer e and a nut f, so that the part E, the washer, and the nut are all firmly compacted together. Thus it will be seen that the two diaphragms support the central casting, and that during their expansion or contraction under the air-pressure and their consequent movements up or down said central casting will likewise be elevated or depressed.

Connection between the chamber below the lower diaphragm and the chamber above the upper diaphragm is had through a vertical passage running along the eccentric stem E, and also passing through the upper diaphragm and superimposed washer and the lower diaphragm and washer beneath, said passage being for a certain portion of its length within the stem E, increased in diameter at h to permit the location therein 01 a valve which may be adjusted to permit the flow of air through the said passage or to obstruct said flow. Evidentlyvarions kinds of valves may be devised for use in this connection. I have in the drawings shown one preferable style, which consists of a rod 2', extending through the enlarged recess, the passage above the same, and projecting a certain distance outside of the upper diaphragm. \Vithin the enlarged recess it this red is enveloped by coiled spring j, the rod which is thus enveloped being severed into two parts, which are separated a short distance, as shown, and said spring being tensioned between collars k on the lower portion of the rod and on the upper portion of the rod. Beneath the collar 79 is a ball Z, forming a ball-valve, which has its seat upon the end of the air passage way beneath the enlarged recess 71. The upper collar 7t has also a seat upon the end of the air passage-way above the enlarged reeess.

The operation of the valve is as follows: In Fig. 1 the valve is shown as open, the ball 1 being removed from its seat and the collar 7:, being removed from its seat. This condition of the valve results from the pressure of the air beneath the diaphragm B, which pressure in pushing up the lower diaphragm has also elevated the central casting, likewise the upper diaphragm, and thus the projecting end of the rod 2' has been brought into contact with an enlargement a on the convex head, thus causing the collar 70 to be sufiieiently removed from its seat to permit the passage of air from the recess h upward through the passage above. The force of the air-pressure upon the ball I will remove this ball from its seat, and hence the air beneath the lower diaphragm will have easy course upward through the air-"passage and into the chamber above the upper diaphragm. \V hen the pressure beneath the lower diaphragm is exhausted, so as to collapse that diaphragm, then the rod 7; will drop along with the other parts, and the spring j will operate to close both the collar 71? and the ball Z- upon their respective seats.

'ithin the cage-like or open head F, which is secured to the projecting sleeve E is a valve G, having its seat upon the end of said sleeve, a tight joint being effected by means of apacking on let into the end of the sleeve upon which the valve-plate tests. This valve G has connected to its upper side the valverod G, enveloped by a spring G, which is tensioned between the upper end of the cap F and the valve proper, and acts to close the valve upon its seat. The valve G is also provided with downwardly projeetin g radial wings G, preferably four in number, which extend downward through the sleeve E and when the valve is in its normal closed position are of snflicient length to extend slightly below the flat plate E.

The tubular extension A", which, we have seen, projects horizontally inward from the wall of the middle part A of the casing, is provided with a valve II, located in the central line of the casing and vertically movable directly beneath the wings of the valve G. The valve II hasa seat upon the packing-rill g n, let into the upper side of the tubular extension A Said valve II has on its upper side four radial wings ll, and on its lower side four other radial wings projecting (lOWllwardly through the vertical passage in the extension A the lower end of said wings carrying a rod Il which passes through a suitable stuffing-box in the wall of the extension A, and is adapted to be brought into contact with the lower flat plate E of the central casting. In Fig. 1, when the airn'essure is beneath the lower diaphragm, the flat plate E, by pressing upon the rod ll during its upward movement, has resulted in removingthe valve 11. from its seat, thus permitting the exhaust to be opened,so that air coming from the brake-cylinder can pass out through the port (Z. In Fig. 2, where the air-pressure has been exhausted from beneath the lower diaphragm, the downward movement of the upper flat plate E has by pressing upon the upper ends of the wings it closed the valve ll, thus closing the exhaust, and the contact of the wings G" with the upper ends of wings ll has resulted in opening the valve G, so that the air from the auxiliary reservoir easily passes through the outlet thus afforded by valve G and on into the brake-cylinder to set the brakes.

I denotes the engineers valve, which in all the drawings I have preferably shown in section. Its construction is simple, being nothing more nor less than a four-way cock, one of whose openings oleads to the air-reservoir; another 19 is the outlet for the exhaust; another (1 is where the train exhaust-pipe is coupled to the engineers valve, and the last 1" is where coupling is made with the train supply-pipe. \Vhen the rotative part I within the casing I of this engineers valve occupies the position shown in full lines in Fig. 1, it will be evident at a glance that the air from the air reservoir can readily pass into the train-pipe, and also that the exhaust from the brake-cylinder which has come through the train exhaust-pipe will enter the valve and pass up through, the exhaustopening 19. When the part I has been rotated to occupy the position shown in dotted lines in Fig. 1, it will be obvious that the exhaust will have no outlet through the engineers valve, since the opening q will be closed. Air may still pass, however, from the air-reservoir into the train-pipe. When the valve assumes the position shown in Fig. 2, the current of air from the reservoir to the train-pipe is obstructed and cut off, and air is being exhausted from the main train-pipe.

It is usual in triple valves or other devices having a similar function to that of my present invention to exhaust the air from the brake-cylinder through an outlet-port leading directly to the atmosphere. Instead of doing this,I now propose to provide what is termed a train exhaust-pipe D, which is to be coupled to the triple valve or similar device and to extend therefrom to the engineers valve. The exhaust air, therefore, instead of rushing into the atmosphere, will pass along this train exhaust-pipe to the engineers valve and have an outlet at that point. It will thus be noted that the engineer will in this way have the exhaustion of the air completely under his control. If he fixes a certain pressure upon the brakes, he can retain and hold that pressure as he may desire. For instance, suppose there is a certain pressure applied to the brakes and that the engineer desires to reduce that pressure without completely removing the brakes. This he can readily do when he has control of the exhaust by simply closing the exhaust, which is ef fected by a simple manipulation of the engineers valve into the position shown in dotted lines in Fig. 1. Thus the brakes can be held set to any desired degree of pressure. In Fig. 1, although the exhaust is closed, as shown in dotted lines, yet air is still passing along the main train-pipe, recharging the auxiliary reservoir, and there is no reduction of pressure in it. It is thought that this combination of atriple valve or similar device, a train exhaust-pipe leading to the engineers valve, and said valve with the train supply-pipe, is novel in pneumatic brake machinery, and considerable stress is here laid upon this feature, as it is thought to be an advance in the art and a great improvement.

It remains to describe the operation of my improved device for applying pneumatic pressure to railway-brakes. The description of the construction of the parts may be sufficient to set forth with clearness the operation of the device; but it is thought best to supplement this with further description of the operation.

In Fig. 1 we have the normal condition of the parts of the device when the brakes are not applied. Air is passing from the air-reservoir through the engineers valve into the train-pipe to my improved regulating device, and the pressure beneath the lower diaphragm is such as to expand the same and force it I upward. Thus it is obvious that the pressure beneath the lower diaphragm is greater than the pressure above the upper diaphragm. Air is passing from beneath the lower diaphragm through the vertical passage in the stem E, the valve therein being open, as shown, into the chamber above the upper diaphragm, and thence to the auxiliary reservoir. The valve G being closed, air cannot go from the auxiliary reservoir to the brake-cylinder. Any pressure in the brake-cylinder is now exhausting through the device into the trainexhaust and out by way of the engineers valve, for the exhaust-valve H is open. Suppose now that it is desired to set the brakes. The engineer will manipulate his valve to the position shown in Fig. 2, so that the air-pressure in the train-pipe and beneath the lower diaphragm may be reduced below what it is above the upper diaphragm. This reduction in. the pressure will cause the collapse of the two diaph ragms, and consequently the closure of the valve Within the stem E and the exhaust-valve H and the opening of the outlet- ,valve G, so that air from the auxiliary reservoir may pass down through sleeve E beneath the valve G and into the brake-cylinder and set the brakes.

We have already seen that when the engineer has released the brakes and desires to fix them at some diminished pressure, or, in fact, to hold them at anydesired pressure, he has the privilege of instantly cutting off the exhaust, and thus retaining the pressure upon the brakes.

In Fig. 5 I have shown the position of the engineers valve when'it is desired to apply straight air to the brakes. In this case the exhaust-valve will be open, as it is in Fig. 1, and the air passing immediately through the trainexhaust from the air-reservoir will go into the brake-cylinder.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is v 1. In a pneumatic brake system, the hereindescribed device for applying and relieving IIO the pressure on the brakes, consisting, essentially, in the combination, with an inelosingcase, of two flexible diaphragms arranged transversely within the case to divide it into three chambers, the ports in said chambers leading to the auxiliary reservoir, brake'eylinder, main supply-pipe, and the exhaustport, an air-passage between the upper and lower chambers, a valve in said passage, an exhaust-valve in the middle chamber, and an outlet-valve between the upper and middle chambers, all substantially as described.

2. In a pneumatic brake system, a device for applying and relieving the pressure on the brakes, consisting in the combination of an inclosing-case, two flexible diaphragms arranged therein, so as to divide said easing into three chambers, the ports in said chambers leading to the auxiliary reservoir, the brake-cylinder, the main supply or train pipe, and the exhaust-port, a valve for controlling the air communication between the end chambers of the casing, the valve for controlling communication between the upper and middle chambers, and the exhausovalve in the middle chamber, all arranged in the manner and for the purpose set forth.

3. The herein-described device for applying and relieving the pressure 011 railwaybrakes, consisting in the combination of an inelosing-case, two flexible dia tihragms arranged within the same to divide it into three chambers, the upper of said chambers having a port leading into the auxiliary reservoir, the middle chamber having-a port lead ing into the brake-cylinder and an exhaustport, and the lower chamber having a port where the main supply-pipe enters, the air passage between the upper and lower chambers containing a valve, the exhaust-valve in the middle chamber, and the outlet-valve between the upper and middle chambers, all arranged substantially as described.

t. In a device for applying and relieving the air-pressure on pneumatic railway-brakes, the combination. of an inclosing-case, two flexible elastic diaphragms arranged therein to make a triple chamber, suitable ports in the iuclosing-case leading to the auxiliary reservoir, the main pipe, the brake-cylinder, and the exhaust, a valve for permitting the passage of air between the upper and lower chambers, an exhaust-valve in the middle chamber for controlling the exhaust, and an outlet-valve between the upper and middle chambers for permitting the flow of air from the auxiliary reservoir to the brake-cylinder, all substantially as described.

5. In a device for applying and relieving the air-pressure e11pneumaticrailwaybrakes, the combination of the engineers valve, the main air-supply pipe, and the device for applying aud relieving the pneumatic pressure on the brakes, consisting, essentially, of an iuclosing-casing, two flexible diaphragms arranged within the same to divide it into three chambers, the upperof said chambers having a portleading into the auxiliary reservoir, the middle chamber having a port leading into the ln'ake-cylinder and an exhaust-port, and the lower chamber having a port where the main supply-pipe enters, the air- )assage between the upper and lower chambers containing a valve, the exhaust-valve in the middle chamber, and the outlet-valve between the upper and middle chambers, all substantially as described.

6. In a device for applying and relieving the pressure to air-brakes, the combination of an inclosing-case made in three parts, two flexible diaphragms secured between the junctions of these parts to divide the easing into three chambers, the upper of said chambers having a port leading into the auxiliary reservoir, the middle chamber having a port leading into the brake-cylinder and an exhaust-port, and the lower chamber having a port where the main supply-pipe enters, a central casting attached to and supported by the flexible diaphragms, a valve arranged in said casting for controlling the communication between the two end chambers, a valve likewise arranged in connection with the casting for controlling communication between the upper and middle chambers, and an exhaust-valve in the middle chamber, all substantially as described.

7. The combination of the inelosing-case having suitable ports leading to the auxiliary reservoir, brake-cylinder, main supply-pipe and exhaust, the two flexible diaphragms secured within said case, a central casting attached to and supported by said diaphragms, and having an air-passage which aifords a connection between the chamber below the lower diaphragm and that above the upper diaphragm, a valve within said passage, an.

outlet valve carried by the upper end of said casting to ailord communication between the air-drum and the brake-cylinder, and an exhaust-val\e, all arranged substantially as described.

8. The combination of the inclosing-case, consisting of the main cylindrical portion A and the end portions A and A, flexible elastic diaphragms l3 and 13, secured within the casing, the central. casting attached to and supported by said diaphragms, the ai rpassage through said eastin g, the exhaust-valve II, and the outlet-valve G, all arranged substantially as described.

9. The combination, with the inclosingcase having suitably-arranged ports and the diaphragms within said case, of the central casting attached to and supported by said diaphragms, and consisting of the eccentric vertical stem E, having the air passage through it containing a valve, the upper flat portions E, having a sleeve E and the lower flat portion E, connected to the lower dia- IIO phragm, the valve G, arranged in connection with the sleeve E and the exhaust-valve H,

arranged in connection with the tubular extension A on the casing, substantially as described.

10. The combination of the inclosing-case, the two flexible diaphragms, the central casting attached to and supported by said diaphragms, the slotted valve-cover F, secured to the upper end of said casting, the valve G, having asteni G, enveloped by a spring G and also having downwardly-proj ecting wings G and the exhaust-valve H, arranged in connection with the tubular extension A of the casing, and having upper wings H and lower wings H carrying a stem H all substantially as described.

11. The combination of the casing, the two diaphragms B and B, secured within it, the air-passage running through said casting between the chamber below the lower diaphragm and that above the upper diaphragm, the valve within said passage consisting of a rod 2', whose upper end is adapted to come into contact with an enlargement a on the casing, collars 7c and k on the two parts of said rod, which is divided near its lower end, and enveloping spring j between said collars, and a ball Z, all substantially as described.

12. The combination of the inclosing-case, two diaphragms B and B, arranged within it, the central casting consisting of the eccentric Vertical stem E, having fiat portions E and E, that are secured to said diaphragms, and having an air-passage that affords connection G on the upper end of the central casting,

and an exhaust-valve H, for controlling the exhaust-port, substantially as described.

1 3. The combination of the inclosing-casing, two diaphragms B and B, arranged within it, suitable ports leading to the main parts of the brake system, an exhaust-valve controlling the exhaust-port, and a central casting supported and carried by the two diaphragms, and having a valve that controls the how of air fromthe auxiliary reservoir to the brakecylinder, substantially as described.

14. The combination of the diaphragms and the casing having an internal projecting extension A at the point where the exhaustport is located, suitablyarranged ports, a valve for regulating the flow of air from the lower end to the upper end of the casing, and the valve for regulating the flow of air from the air-drum to the brake-cylinder, and an exhaust-valve H, having upper wings H and lower wings H terminating in a stem H substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

NATHANIEL J. PRITGHARD.

' Witnesses:

BENN C. FECHTIG, DAVID W. FLEQKNER. 

